Filtered Lookups, Validation Rules, and Order of Execution

October 6, 2009 · Filed Under Configuration, Native Application, New Features, Tips and Tricks, Winter 10, salesforce.com 

Reading the cheatsheet for Filtered Lookup (beta), I noticed an interesting line:

Lookup filters function similarly to validation rules when you save a record. That is, actions that cause related records to save, such as changes to a roll-up summary fields, also trigger the lookup filters on the related record and block the save.

The implications for this are massive. Let's explore two examples:

Example 1: Filter as Validation Rule from Parent Record

  • We create a lookup on a Child object to Parent.
  • We filter the lookup to EXCLUDE Parent.Status = 'Closed' (Parent.Status is only Open or Closed.)
  • We can edit the Child records as long as the Parent Status is not Closed.
  • When Parent.Status is changed to Closed, existing related Child records are not affected...
  • BUT if we attempt to edit a Child when the Parent is Closed, Force.com will throw an error (which we can customize) beause that the Lookup is invalid.
  • (and clearly we cannot add new Child records either)

Conclusion: Thus, Filtered Lookups act much like Validation Rules. A quick experiment shows that Filtered Lookup errors actually fire before Validation Rules.

Example 2: Filter as Validation Rule on Roll-Up Summary (from Child Record) - what the line above was referencing

  • Use the above example, but change the lookup to a master-detail relationship
  • Create a Roll-Up Summary field to count all child records
  • Prevent saving more than 10 child records for one parent record

Here, we have triggered a filter error without touching a parent record, yet we throw an error based on a value on the parent record.

This second example is significant because we could already prevent more than 10 child records from saving, but doing so required a Roll-Up Summary field on the parent object AND a Validation Rule on the child object. Now we can replace the Validation Rule with the Lookup Filter, though we still need the Roll-Up Summary field. Whether or not this simplifies things is definitely up for debate...

Conclusion

This is a very powerful feature! Thanks to salesforce.com for rolling it out, even in beta form.

Real world example: The above example would be great for Time Sheet Entry and Time Sheet Header objects, as they would create, in effect, a validation rule on the Header record preventing editing of any child records. Awesome!

For further reading, check Salesforce Help's Lookup Filters examples.

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3 Responses to “Filtered Lookups, Validation Rules, and Order of Execution”

  1. manudewan on October 6th, 2009 09:20

    Useful new post by @x2od: New Force Squared post: Filtered Lookups, Validation Rules, and Order of Execution http://bit.ly/39N7wl

    This comment was originally posted on Twitter

  2. nonprofitcrm on October 13th, 2009 06:01

    Filtered Lookups, Validation Rules, and Order of Execution http://j.mp/2u4Hem

    This comment was originally posted on Twitter

  3. nonprofitcrm on October 13th, 2009 06:01

    Filtered Lookups, Validation Rules, and Order of Execution http://j.mp/2u4Hem

    This comment was originally posted on Twitter

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